ATLANTA -- Gay rights advocates say a bill being discussed in the state legislature would open the door to state-sanctioned discrimination against gays and lesbians.

Opponents of the bill packed a committee hearing late today to speak against the measure, which is couched in religious freedom.

The bill is called the "Preservation of Religious Freedom Act." It says religious liberty occupies a preferred position in state law.

The author of the bill, Rep. Sam Teasley (R-Marietta) says that it is designed to protect religious freedom.

"My faith teaches me that everyone needs to be treated with dignity and respect, and this law does nothing to change that," said Teasley.

Teasley said that he modeled the bill after a similar federal law. He said that there needs to be more protection of people's freedom to exercise religion.

Opponents say it could be used to discriminate against groups, such as gays.

"A shop owner could say, 'You look like a gay couple, I'm not going to serve you in this restaurant,'" said Jeff Graham of Georgia Equality. "This is the sort of widespread discrimination that does get opened up by a bill like this."

Teasley responded, "There has not been a case that I'm aware where that has ever been used -- and certainly not successfully used."

House Rep. Simone Bell (D-Atlanta), who is openly gay, spoke out against the bill. Responding to Teasley's comments, she said, "I think it's easy for someone to say that who doesn't experience the discrimination that we experience on a daily basis. And we know that once something is codified in law, that opens up the door for people to feel like they have a need or responsibility to discriminate."

Teasley said that he has introduced a couple of amendments to the bill that he says will alleviate many concerns. He said he would elaborate on those at a later time.

A second hearing on that bill is scheduled later this week.

The bill was one of two very contrasting efforts potentially impacting gay rights at the Georgia Capitol. Another bill would legalize gay marriage. Such unions are currently unconstitutional in Georgia.

Atlanta Mayor Kasim Reed was at an event launching a regional campaign to win hearts and minds across the South to gay marriage.